Everyone thought rodents didn't menstruate naturally, but in a surprising discovery it turns out that the spiny mouse actually does. Having that human-like cycle opens up new possibilities for medical research into reproductive diseases, reports Nature.

Welcome to the club, little ladies, although I'm not sure you ever wanted to join this one.

This is 2016, but conditions affecting women's reproductive cycles are still poorly understood. Medical treatments for PMS and endometriosis are limited, and as any woman suffering from either can tell you, current treatments have limitations. And unfortunately lab mice don't menstruate unless their ovaries are taken out and they're given crazy high doses of hormones, which isn't ideal for anyone.

In order to study menstruation-related diseases, researchers have been relying on baboons, an animal model that is expensive and time-consuming, Nature reported.

Enter reproductive physiologist Hayley Dickinson and her team at Monash University in Clayton, Australia. Turns out the spiny mouse (Acomys cahirinus) actually does get a visit from Aunt Flow. Reporting recently in the BioRxiv preprint server for biology (abstract), Dickinson's team describes the first observation of cyclic endometrial shedding and blood in the vaginal canal for virgin female spiny mice.

The team carefully tracked the mice's periods and treated a control group of lab mice the same way. They also dissected spiny mice uteri at different stages of menstruation. But how on earth did everyone miss this for so long? "The answer, as with many discoveries in science, is that no one really looked," Dickinson told Nature.

"[This] provides an unprecedented natural non-primate model to study the mechanisms of menstrual shedding and repair," her team wrote in their abstract. It also could also be useful in furthering our understanding of human specific menstrual and pregnancy associated diseases, they added.

Just getting more stuff tested on female mice was a struggle. In 2014, the National Institutes of Health introduced a policy requiring that funded studies use both female and male mice or justify why only one sex was used. This was after nearly two decades of testing that relied mostly on male mice, resulting in drugs that had significantly different effects for women. Like Ambien.

Honestly, thinking so much about animal testing does make me uneasy. I lost a little humanity in New York City once during a rodent infestation and can also sympathize with the animal rights people. At the same time, mice have saved countless human lives.

Now they could help us develop miraculous treatments for conditions that cause intense pain and suffering. Maybe flying the red flag won't mean putting up a white one of surrender, too.